Several investigators have used radiography to study sandstone, siltstone, and recent sediments. In studying fine-grained sediments, radiographic techniques, if used alone or in conjunction with other techniques such as X-ray diffraction, electron microscope, petrographic and binocular microscope, chemical and field techniques, can add materially to knowledge of the structures and textures of fine-grained sediments. Some of the advantages of the radiographic techniques are: (1) larger and thicker samples can be used; (2) the techniques save time; (3) structure and texture are observed clearly on film which might be missed by other methods of investigation; and (4) the relation of the various structural and textural features can be observed for the entire specimen. Some of the disadvantages are: (1) microstructures cannot be observed; (2) structural and textural features having the same absorption capacity for X-rays are not recorded on the film; and (3) film is not easily studied microscopically for microscopic structures and textures.

Some of the structures which have been observed are cracks, trails by animals, slickensided surfaces, concretions, fossils, small faults which cut only a few laminae, erosion of one or more laminae, flow structures, expansion and contraction of the same laminae laterally, and vertical transition from well-laminated to poorly laminated sediments. The textural features shown are graded bedding, differences in the thickness of laminae, smaller laminations in thicker laminae, and some radiographs of mudstone that look like fleecy clouds.

All these structures and textures are related to the environments of deposition and to the environments during consolidation after deposition.

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